In the previous chapter, we explored indoors rendering algorithms in detail and learned all about dungeons, castles, and houses. Now we will move out of the building and into the great outdoors. We will focus on hills, trees, and valleys, where we can see for miles away. Rendering outdoors scenarios is a completely different business than indoors rendering. Luckily, some robust methods have been devised through the years, which ensure that we can render virtually any outdoors scene with reasonable performance. Let's study these popular algorithms in detail.